Try it and report back. I'm genuinely curious to see if it's what you're claiming it to be on your end, cause I have yet to see any FOSS Lemmy apps getting triggered in DDG, no matter what links I click. Maybe I'm just lucky?
The biggest alarm in this thread is everyone thinking that apps are at the whim of advertising companies and completely innocent on their part. They are not. Ads can work without trackers and devs can prevent users from being tracked within embedded browsers.
Almost always digital on my tablet or phone these days (I have a Kindle too but just can't get used to the display), but I'll buy physical copies to keep and/or give away if I really like them.